RC coupling filter, especially an input filter, for receivers of centralized ripple control systems

Abstract

A RC coupling filter, especially an input filter for receivers of centralized ripple control systems, with at least two similar active RC four terminal networks with at least one amplifier each, each four terminal network having an input and every two adjacent RC four terminal networks being interconnected by means of exactly one coupling admittance connected between the inputs of the adjacent RC four terminal network, wherein, if the signal to be filtered is introduced into the input of the first RC four terminal network, a feeding admittance is connected at one end to the input of the first RC four terminal network, the signal to be filtered being introduced into the other end of the feeding admittance.

We claim: 
     
       1. A coupling filter, esspecially an input filter for receivers of centralized ripple control systems, comprising; a plurality of similar four terminal networks, each one of said plurality of four terminal networks having an input and an output;   every two adjacent four terminal networks being interconnected by no more than a single coupling admittance;   each one of said plurality of four terminal networks being an active RC four terminal network having at least one amplifier;   wherein said single coupling admittances are connected between the inputs of each two adjacent RC four terminal networks; and   wherein the input of the first RC four terminal network is connected to a feeding admittance.   
     
     
       2. The coupling filter as claimed in claim 1, wherein with respect to each pair of adjacent four terminal networks the input of the first of each said pair of four terminal networks is uncoupled with respect to the output of the second of each said pair of four terminal networks. 
     
     
       3. The coupling filter as claimed in claim 1, wherein the signal to be filtered is introduced into the noninverting input of the amplifier of the first RC four terminal network. 
     
     
       4. The coupling filter as claimed in claim 3, wherein each four terminal network includes a second amplifier, the noninverting input of the second amplifier of each RC four terminal network is connected by way of a first tuning admittance to the output of the first amplifier and by way of a second tuning admittance to the ground. 
     
     
       5. The coupling filter as claimed in claim 4, wherein the tuning admittances are embodied in ohmic resistances. 
     
     
       6. The coupling filter as claimed in claim 3, wherein each RC four terminal network is designed as a resonator with two amplifiers, the inverting inputs thereof being interconnected. 
     
     
       7. The coupling filter as claimed in claim 1, wherein each four terminal network includes a second amplifier, the noninverting input of the second amplifier of each RC four terminal network is connected by way of a first tuning admittance to the output of the first amplifier, and by way of a second tuning admittance, to the ground. 
     
     
       8. The coupling filter as claimed in claim 1, wherein each RC four terminal network is designed as a resonator with two amplifiers, the inverting outputs of which are interconnected.